CO-induced structural changes of supported Rh promoted by NO

被引:28
作者
Novak, E [1 ]
Sprinceana, D [1 ]
Solymosi, F [1 ]
机构
[1] HUNGARIAN ACAD SCI,CTR CATALYSIS SURFACE & MAT SCI,REACT KINET RES GRP,H-6701 SZEGED,HUNGARY
基金
匈牙利科学研究基金会;
关键词
gem-dicarbonyl; NO; rhodium;
D O I
10.1016/S0926-860X(96)00251-7
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The effects of NO on the CO-induced structural changes of Rh deposited on SiO2, MgO and TiO2 are investigated in the temperature range 110-503 K by means of infrared spectroscopy. It was observed that the addition of NO to CO dramatically enhanced the development of gem-dicarbonyl, Rh-I(CO)(2), from Rh-x-CO species - indicative of the occurrence of the oxidative disruption of the Rh-x cluster - for all the three samples at 233-300 K. This is explained by the formation of a strong bond between NO and Rh-x crystallites which weakens the Rh-Rh bond. It is assumed that the NO and its dissociation product, the adsorbed O, participate in the oxidation of isolated Rh-0 atoms to Rh-I ions. On the other band, the presence of NO slowed down the conversion of gem-dicarbonyl into Rh-x-CO at and above 448 K to a great extent, indicating that NO retards the reductive agglomerization of Rh-I to Rh-x crystallites on these supports.
引用
收藏
页码:89 / 101
页数:13
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